you could make a router cross slide carriage for a dremel, along these kinds of lines:
http://www.idealtools.com.au/images/page3812.jpg
Some routers have holes bored through the base too for the side fence. If you could pick up some silver steel rod it'd make a nice smooth running slide. Alternatively you could make a new base plate for a router base and simply drill all the holes at once so as to ensure alignment.